module Transcriptic::Command

  # list commands and display help
  #
  class Help < Base
    PRIMARY_NAMESPACES = %w( analyze data history run status sequences)
    
      # help [COMMAND]
      #
      # list available commands or display help for a specific command
      #
      def index
        if command = args.shift
          help_for_command(command)
        else
          help_for_root
        end
      end

      alias_command "-h", "help"
      alias_command "--help", "help"

      def self.usage_for_command(command)
        command = new.send(:commands)[command]
        "Usage: transcriptic #{command[:banner]}" if command
      end

    private

      def commands_for_namespace(name)
        Transcriptic::Command.commands.values.select do |command|
          command[:namespace] == name && command[:command] != name
        end
      end

      def namespaces
        namespaces = Transcriptic::Command.namespaces
        namespaces.delete("app")
        namespaces
      end

      def commands
        Transcriptic::Command.commands
      end

      def legacy_help_for_namespace(namespace)
        instance = Transcriptic::Command::Help.groups.map do |group|
          [ group.title, group.select { |c| c.first =~ /^#{namespace}/ }.length ]
        end.sort_by { |l| l.last }.last
        return nil unless instance
        return nil if instance.last.zero?
        instance.first
      end

      def primary_namespaces
        PRIMARY_NAMESPACES.map { |name| namespaces[name] }.compact
      end

      def additional_namespaces
        (namespaces.values - primary_namespaces)
      end

      def summary_for_namespaces(namespaces)
        size = longest(namespaces.map { |n| n[:name] })
        namespaces.sort_by {|namespace| namespace[:name]}.each do |namespace|
          name = namespace[:name]
          namespace[:description]
          puts "  %-#{size}s  # %s" % [ name, namespace[:description] ]
        end
      end

      def help_for_root
        puts "Usage: transcriptic COMMAND [command-specific-options]"
        puts
        puts "Primary help topics, type \"transcriptic help TOPIC\" for more details:"
        puts
        summary_for_namespaces(primary_namespaces)
        puts
        puts "Additional topics:"
        puts
        summary_for_namespaces(additional_namespaces)
        puts
      end

      def help_for_namespace(name)
        namespace_commands = commands_for_namespace(name)

        unless namespace_commands.empty?
          size = longest(namespace_commands.map { |c| c[:banner] })
          namespace_commands.sort_by { |c| c[:banner].to_s }.each do |command|
            next if command[:help] =~ /DEPRECATED/
            command[:summary]
            puts "  %-#{size}s  # %s" % [ command[:banner], command[:summary] ]
          end
        end
      end

      def help_for_command(name)
        if command_alias = Transcriptic::Command.command_aliases[name]
          display("Alias: #{name} redirects to #{command_alias}")
          name = command_alias
        end
        if command = commands[name]
          puts "Usage: transcriptic #{command[:banner]}"

          if command[:help].strip.length > 0
            puts command[:help].split("\n")[1..-1].join("\n")
          end
          puts
        end

        if commands_for_namespace(name).size > 0
          puts "Additional commands, type \"transcriptic help COMMAND\" for more details:"
          puts
          help_for_namespace(name)
          puts
        elsif command.nil?
          error "#{name} is not a transcriptic command. See `transcriptic help`."
        end
      end
    
  end

end